This invention relates to an apparatus for testing circuit boards, and in particular, for testing a circuit board having a high density of probe points such as a multi-layer printed circuit board or multi-chip module.
As the density of component placement on circuit boards increases, it is becoming more difficult to provide circuit board testing equipment which can match and test the boards as required.
Known probe panels use probe needles which are subject to additional problems such as breakage and wear. This results in lost productivity due to down time and also due to bad yields because of faulty test equipment. Problems may arise as integrated circuit technology reaches the point of fabricating components directly upon large circuit boards. Testing will require greater probe density than that presently available.
Current printed circuit board testing equipment, such as a "bed-of-nails" testing device, has a probe density limited to between 100 probes per square inch to 200 probes per square inch. In addition, each probe panel of the "bed-of-nails" testing device must be carefully designed to "match" the circuit board to be tested. The custom-designed probe panels, called "fixtures", represent a substantial cost of the testing device. Moreover, these fixtures are limited only to the particular circuit board for which they were designed.
Therefore, what is desired to overcome the problems cited above is a probe panel with densities higher than 200 probes per inch, that has improved reliability and that would be universally adaptable to any circuit board desired to be tested.